Ligation of tissues and organs is an essential stage of a surgical intervention, which largely determines the result and the very possibility of the operation. The effectiveness of ligation, in turn, depends on the ligating instrument, which must be such as to provide aerostatic and hemostatic ligations. A ligating instrument must be capable of adjusting the ligation spacing depending on the thickness of the tissue being ligated over a broad range so as to meet all practical requirements. It must also be as compact as possible so that it can be easily handled in the operative wound.
There is known an instrument for ligating blood vessels with metal staples according to U.S. Pat. No. 3,079,608. It comprises an anvil body and a staple driving body held together by a detachable joint and a locking means. The staple driving body has a working portion with staple channels extending transversely to the longitudinal axis of the staple driving body. The channels accommodate U-shaped staples and staple pushers which serve to push the staples out of the channels during ligating. In pushing out the staples, the staple pushers interact with a tapered wedge movable along the working portion of the staple driving body.
The wedge is mounted on the end of a strip close to the working portion of the staple driving body. The opposite end of the strip is connected to a carriage movably arranged in a recess provided in the staple driving body.
The anvil body has a working portion which is opposite the working portion of the staple driving body during operation. The working portion of the anvil body carries an anvil. As staples are pushed out from the staple channels, they are brought into engagement with the anvil and their ends are bent. In order to bend the ends of the staples, the anvil is provided with two rows of hollows. With the ligating instrument fully assembled, the rows of hollows extend along the entire length of the working portion of the anvil body opposite the staple channels of the staple driving body.
The locking means for holding together the staple driving body and anvil body is a rack-and-pinion means. As the staple driving body and anvil body are brought together or apart, the rack and pinion teeth are successively thrown into engagement and discretely lock the working portions of the staple driving and anvil bodies in relation to each other, thus making it possible to adjust the ligation spacing depending on the thickness of the tissue being ligated.
The ligating instrument in question is disadvantageous in that the ligation spacing can only be adjusted over a very narrow range. The instrument is too long, for its overall length is a sum total of the length of the working portion of the staple driving body, which corresponds to the length of the suture, and the length of the strip carrying the wedge, which is as long as the working portion of the staple driving body.
The design of the ligating instrument in question fails to increase the range of ligation spacings, for increasing that range seriously impairs the quality of the suture along its length. The reason for this lies in that the working portions of the staple driving body and anvil body, which compress the biological tissue, do not move in parallel with each other.
The above disadvantages are partially eliminated in a ligating instrument according to USSR Inventor's Certificate No. 886,897, which comprises an anvil body and a staple driving body. The staple driving body has a working portion with a longitudinal groove formed by its lateral walls. The longitudinal groove accommodates a magazine whose external shape is identical with the shape of the groove. The magazine contains a plurality of U-shaped staples received in sockets uniformly spaced over the entire length of the magazine. The same sockets accommodate staple pushers.
Each staple pusher is shaped as a right-angle prism with a bevelled surface facing the bottom of the magazine. The opposite side of the prism, which faces the staples and comes in contact with them, is flat. The staple driving body is provided with a handle having a ring, which is intended to be grasped by the hand. In pushing out the staples, the staple pushers interact with a tapered wedge which is movable along the working portion of the staple driving body. The wedge is mounted on the end of a strip and is close to the working portion of the staple driving body. The opposite end of the strip is connected to a carriage movably arranged in a groove provided in the staple driving body.
The anvil body has a working portion which is opposite the working portion of the staple driving body when the two bodies are held together. A longitudinal groove is provided over the entire length of the anvil body. This groove is formed by the lateral walls of the working portion of the anvil body. It receives an anvil with hollows. Staples are brought into engagement with the hollows, whereby their ends are bent for ligation.
The ligation spacing is adjusted over a desired range by moving the anvil toward the working portion of the staple driving body by a means for adjusting the ligation spacing, which is accommodated in the working portion of the staple driving body.
The means for adjusting the ligation spacing is a crankshaft with a handle for rotating the crankshaft. The anvil is a right-angle prism. Hollows are provided on the lateral side of the prism, which faces the working portion of the staple driving body and compresses the biological tissue being ligated. The hollows are arranged strictly opposite the sockets of the magazine.
The anvil is provided with a longitudinal recess which receives the crank of the crankshaft. As the crankshaft is rotated by the handle, the anvil moves toward the working portion of the staple driving body, changing the distance between the surfaces of the anvil and the working portion of the staple driving body which compress the biological tissue. In this way the ligation spacing is adjusted.
The anvil body has a handle with a ring. The handle is designed to be grasped by the hand.
The ligating instrument further incorporates a detachable joint and a locking means which serve to hold the anvil body and the staple driving body together. The detachable joint is located at the point where the working portions of the anvil body and staple driving body are joined together. The detachable joint is an axle mounted on the staple driving body and having its end received in a hole provided in the anvil body. The locking means is a two-tooth rack-and-pinion means arranged in proximity to the handle with the ring.
In the latter ligating instrument, the ligation spacing adjustment means is not kinematically coupled to the wedge. This necessitates the use of said strip, which increases the length of the staple driving body and anvil body and the overall length of the instrument, since the latter is a sum total of the length of the working portion of the staple driving body, corresponding to the suture length, and the length of the strip carrying the wedge, which is as long as the working portion of the staple driving body.
The ligating instrument under review is hard to manipulate in an operative wound. It is quite difficult to bring its working members to the suture area in order to ligate a lung between the lobes.